General Background
Medical practice requires devices for attaching and securing a needle, catheter or cannula to a patient for intravenous injections, blood transfusions, anesthesiology, drainage or feeding, and other percutaneous intubations. In general, experience has shown that such devices should preferably provide the following characteristics:
clean and sterile; PA1 comfortable for the patient; PA1 secure in attaching and holding the catheter safely to prevent accidental removal or disengagement; PA1 resilience to absorb some degree of movement without damage or discomfort to the patient; PA1 provide visibility for continuing inspection; PA1 efficient to apply, use, remove, and replace; PA1 inexpensive; and PA1 without increasing the relative risk of infection.
Many types of catheter attaching devices are available in this field; yet few, if any, efficiently provide these desirable characteristics. Many are deficient or inefficient in one or more capabilities, requiring medical practitioners to compromise for particular circumstances.
Basically, a catheter can be, and often is, secured with conventional medical adhesive tape and auxiliary materials. A gauze pad is positioned at the point of penetration, and strips of adhesive tape are torn and applied to the pad, catheter and tubing in a manner calculated to minimize risk of accidental injury or removal of the needle from the patient by inadvertent movement.
In many instances, if protective schemes have been used, they have consisted of temporary use of available materials such as towels and portions of styrofoam cups held in place with adhesive tape. Such schemes are clumsy and obstruct visual inspection of the needle or area of injection as well as requiring untaping of the temporary protector to make certain of the well being of the patient and the security of the catheter. Other devices place pressure or strain on the intravenous needle rather than providing protection.
The effectiveness of these contrived methods, including number of strips of tape, manner of applying them, and degree of protection, depends on the skill and ingenuity of the medical practitioner in applying the tape and materials. Thus adhesive tape attachment is time consuming, inefficient and expensive, can be clumsy to use and replace, and most often obstructs the view and precludes ready visual inspection. Viewing of the penetration incision is dependant upon the pattern of which the attendant applies the devices and strips of tape, as well as the size and arrangement of the gauze pad. By obscuring visibility of the penetration site, infiltration and infection may be undetected. Many types of schemes and attaching apparatus have been devised and are available in attempts to solve this problem, with varying complexities.
Prior Devices for Attaching Catheters
Buttaravoli U.S. Pat. No. 3,918,446 uses a sandwich design of pads to hold the catheter, which must be moved underneath and the inserted needle arranged between the layers, requiring delicate movement of the catheter. The pads obscure visibility of the needle and significant area surrounding the catheter.
Cutruzzula U.S. Pat. No. 4,059,105 uses a unitary T-shaped, laminated, folded harness, having a narrow, lower body portion 12 with an elongated opening 16 to expose the insertion site at which the cannula 34 enters the patient, and a wide, upper head portion 14 which is then folded and superimposed upon the narrow portion 12, to secure the catheter and cover the opening 16. The structure and adhesive are opaque and obstruct visibility of the penetration site and apparatus, although the opening 16 of the site and cannula 34 may be viewed when the upper portion 14 is unfolded for inspection.
Jacobs U.S. Pat. No. 4,397,641 uses a rigid annular support plate 30 and pad 46, securable to the patient by an adhesive patch 50, and having an inclined catheter support bracket 40, and arcuate passageway for mechanically isolating the catheter tubing. It has concentric apertures 44 and 48 for an open area of the patient's skin through which the cannula is inserted, although Jacobs appears not to recognize the need for aerating the site to ambient air to inhibit risk of infection, and teaches away from such advantage by noting in column 4 line 63 that the entire area over the puncture site may be protected by gauze and tape as needed in order to maintain the puncture site free of contamination, and tape may be periodically removed for inspection.
Filips et al U.S. Pat. No. 4,633,863 discloses an arterial anchor bandage which emphasizes need for visible inspection, but includes opaque structures which obstruct from view the skin surrounding a puncture site. Filips recites need for circulation of air at penetration site, but is a closed bandage which provides only pores for restricted air circulation. Filips discloses a transparent bulbous shield 12 which permits some amount of visible inspection, which protrudes above a tri-lobed adhesive outercovering layer 18, and which has an opening 14 sized to receive the tube from an arterial catheter and to permit rotation of the catheter without removal of the bandage to check positionality of catheter. Various features of the structure permit its application very close to articulated joints at radial, brachial and femoral sites of a patients anatomy. In comparison, Davis' instant invention of this application provides structural simplicity which permits the Davis device to be applied anywhere. Filips recites that air circulation aids in healing and keeps the skin healthy, but Filips makes only the outer cover of porous material and may alternatively be provided with a plurality of pores which permits only restricted ability to circulate air (efficacy unknown) and reduce moisture buildup. Filips teaches use of an absorbent layer 28 between the shield 12 and the skin of the patient to provide a wicking function to remove fluids from the insertion area; whereas Davis' device provides entirely open access to air circulation and aeration by virtue of its totally open center.
Abraham U.S. Pat. No. 4,669,458 discloses a holder 10 with a flat base 12 and adhesive bottom with a aperture 16 in the middle, having a clear plastic, replaceable window 14 with adhesive bottom 22 placed over the aperture, so that the insertion site lies in the middle of the aperture, and the clear window covers and protects the needle, allowing the insertion site to be observed. A see-through gauze pad 28 with antibiotic salve may be removably placed underneath the clear window. It is also possible to use a plastic material such as Saranwrap for the window 14. Abraham includes opaque structure which obstructs vision of the site; provides no aeration; and teaches away from aeration by providing clear plastic covers 14 over the needle insertion site.
Nowak U.S. Pat. No. 4,699,616 provides an adhesive barrier pad 11, with an opening 14 aligned with the fenestration in the body wall, the pad 11 having a molded plastic catheter support structure 12 and a planar base 21, two support arms 24a and b, and a pair of elongated clamping bars 25 and 26 for clamping the catheter. Slits 15 and 22 are provided for spreading the edges of the pad 11, base 21, and entry slit 15, and urging the catheter laterally into the opening 14, exposing the area of the incision for inspection; but the structure, base, pad, adhesive and apparatus assembly are opaque, obstructing view of the site; require maneuvering for assembly and obstruct and impair visibility. Nowak does not teach aeration of the penetration site; uses a pressure sensitive adhesive which in column 3 line 30 preferably also performs a sealing function in protecting the skin against fluid contact; and in column 6 line 9 provides that a nurse or doctor might cut the pad to form a central opening of greater size to suit the particular catheter exit site.
Hogan U.S. Pat. No. 4,869,719 provides a plastic retaining plate 52 anchored to the patient's skin 26 with adhesive, having a cover 62 for a chamber for packing gauze 66 where the catheter enters the patient, with bushings, sleeves, and spacers to adjust length of the inserted catheter. A cut 60 in the retaining plate 62 permits the threading of the catheter tube 20 through the aperture 58 and the positioning of the bushing 28. Relatively small openings 64 in the cover 62 permit only limited and obstructed visual inspection of the cotton gauze 66 so that it can be replaced when necessary, and also provides for limited amount of aeration of the incision, but does not teach combined visibility and aeration to inhibit bacteria.
Hasketh U.S. Pat. No. 4,874,380 discloses a flange 10 having a central hole 12, mounted on a pad 14, with an upstanding post 16, with an elongated tab 22, ratchet teeth 24, and detente 28, for griping the catheter, and a slit extending from the hole 22 to its periphery for introducing the catheter and tubing without having to thread the whole length through the device. In Hasketh, the central hole 12 is only somewhat larger than the diameter of the catheter.
Simon U.S. Pat. No. 4,883,053 provides a retractable, foldable, self-supporting, angulator device, for precise angular aiming, holding and percutaneous insertion of surgical objects such as a needle into the tissues of a subject. The base plate 12 with center aperture 20 will be positioned at the insertion site overlying the tissue to be penetrated, adjustably holding the needle at precise angle for insertion through center aperture 20.
Kalt U.S. Pat. Nos. 4,919,654 and 4,966,590 disclose a clamp for holding a catheter, a flap, securing surfaces, and a resilient pad for adhering to the patient. The resilient pad is deformable such that slight rotation or translational movement will deform the pad rather than breaking the adhesive bond between. The base has a window for positioning the clamp on the patient with the intravenous puncture positioned for view through the window 17, with a sterile, breathable, clear, waterproof membrane 15, covering the window opening 17 and having a slot for allowing a needle to puncture a patient's skin at a point located under the membrane. The membrane 15 seals and protects the skin puncture 90 by the needle 91, which extends through the membrane 15 at puncture hole 18. Kalt discloses that a resilient adhesive pad in contact with an IV needle structure provides secure means for holding the catheter and tube against rotational or translational movement, tending to deform, twist, and move with the catheter and tube when urged to rotate slightly. Kalt does not teach visibility combined with open aeration to inhibit growth of bacteria.
Sallee U.S. Pat. No. 5,112,313 shows a molded, plastic cover, that is transparent so that one can see through the thin walled body 14, to view the needle catheter secured inside and attached to the patient with adhesive tape. There can be openings 28 in the roof 26 of the housing 12, to provide a limited amount of air circulation to the hollow area within the housing 12. The cover or roof may be hinged so that access to the intravenous needle can be had without removing the adhesive tape. The roof can have transparent magnification to enable viewing of the intravenous needle insertion site.
Several manufacturers market self-adhesive sterile, transparent plastic film as a covering for wounds and incisions. One such material is covered by Hodgson U.S. Pat. No. 3,645,835 which discloses a moisture-vapor-permeable, pressure-sensitive adhesive material as a surgical drape, suture strip, adhesive dressing, bandage, plaster, tape, etc., comprising a backing material and pressure sensitive adhesive on one surface, being both moisture-vapor-permeable and unaffected by water and nonpermeable to liquid water. Such materials are useful where it is desirable to have an adhesive material which is permeable to water vapor, but which is not permeable to liquid water, micro-organisms, and particles of dirt, in order to provide the desired covering without causing maceration, steeping and wasting-away, due to occlusion of water from transepidermal water loss from the body.
The 3-M Company, Medical-Surgical Division, has marketed a self-adhesive sterile, transparent plastic film intended as a medical dressing. The 3-M product is marketed as Tegaderm.TM. material under license from Hodgson U.S. Pat. No. 3,645,835. Another product of this type is marketed as BIOCLUSIVE.RTM. Transparent Dressing, a Johnson & Johnson trademark, by MEDI-FLEX , Overland Park, Kans. 66210. Similar commercial materials are believed to be available from other sources. These materials have the advantages of being non-complex, transparent for visual inspections, and securely adhering and covering medical applications, and some are permeable to water vapor, thus providing visual inspection, keeping the application clean, and avoiding maceration.
Experimentation with Transparent, Self-Adhesive Film as an Attachment Device for Securing Catheters
There has been experimentation in use of self-adhesive sterile, transparent plastic materials as means to secure intravenous catheters to the body of the patient. A solid rectangular or circular sheet of the transparent self-adhesive film has been used, large enough to bind the catheter to the patient's skin, covering a substantial portion of the catheter and surrounding skin of the patient. The sheet of film is applied directly over the catheter site and skin, so that the adhesive film securely grips the structure of the catheter, including in some cases also part of the attached tubing, and as much of the patient's body as is desired by the medical practitioner.
Recognizing the Problem with Transparent Film
Initially, transparent film material appeared to provide a desirable device for securing medical catheters. The tenacity of the adhesive, and the resilience, and somewhat flexibility, of the material, appeared to provide a secure and shock absorbing attachment. Transparent film material is transparent, sterile, less complex, easier to use and less expensive than prior devises and methods.
However, for percutaneous injections, these transparent film materials suffer a serious disadvantage. All of them double or triple the intravenous site infection rate due to the maintenance of a warm moist environment under the plastic film, which encourages growth of bacteria at the site. Consequently, in spite of ready commercial availability of this material, and in spite of its ease of use and obvious mechanical advantages as an efficient and transparent attaching device for catheters and cannulas, such uses, as previously configured, have been reported by the Journal, American Medical Association, to involve significant increase in relative risk of infection.
In medical publication, "Transparent Polyurethane Film as an Intravenous Catheter Dressing", by Karen K. Hoffman et al., Journal American Medical Association, Apr. 15, 1992, Vol. 267, No. 15, page 2072, it was reported that "use of transparent dressings on central venous catheters was significantly associated with an elevated relative risk (RR) of catheter-tip infection . . . Catheter-related sepsis . . . and bacteremia . . . were both associated with an elevated RR. Use of transparent dressings on peripheral catheters was associated with an elevated RR on catheter-tip infection . . . but not phlebitis . . . , infiltration . . . , or skin colonization . . . The results demonstrated a significantly increased risk of catheter-tip infection with the use of transparent compared with gauze dressings when used with either central or peripheral catheters. An increased risk of bacteremia and catheter sepsis associated with the use of transparent compared with gauze dressings for use on central venous catheters was suggested."
The report stated "The mechanism by which transparent dressings increase catheter-associated infection is likely the promotion of bacterial growth (Aly R., Shirley C., Cinico B., Maibach Hi. Effect of prolonged occlusion on the microbial flora, pH, carbon dioxide and transepidermal water loss on human skin. J. Invest Dermatol. 1978; 71:378-381.), which may be related to the inadequate moisture vapor permeability. (Craven Del., Lichtenberg DA, Kunches M, et al. A randomized study comparing a transparent polyurethane dressing to a dry gauze dressing for peripheral intravenous catheter sites. Infect Control. 1985; 6:361-366.)"
The report further concluded "Based on our data, we suggest that the increased infection risks associated with transparent dressings be considered an institutional decision . . . New, more permeable dressings may result in reducing the infection risks associated with this type of dressing."
Solution to the Problem; and Concept of the Invention
This Applicant has found and herein discloses that permeability, porosity, and even perforation of the transparent, adhesive dressing materials is not enough--the solution to this problem is to keep the immediate penetration site open to ambient air which will aerate the site and tend to keep it dry, thus inhibiting growth of bacteria. The solution involves a conceptual change in the design and configuration of the transparent, self-adhesive film dressings to be used as a securing device. The film must remain transparent for inspection, and must substantially cover, efficiently adhere, and secure the catheter to the skin of the patient. But, to inhibit growth of bacteria and reduce the relative risk of infection, continual and substantially open, fenestra aeration must be provided to the penetration site. The open aperture must be large enough to allow the site to remain dry. In this manner, it is hereby disclosed that the many advantages of transparent self-adhesive film may be safely and prudently used while avoiding the problems of increased relative risk of infection. These are major advantages which surpass prior devices. The resilient material tends to act with the patient's skin to absorb deflections and move with the catheter and tube when urged to rotate or translate slightly. Significant movement of the catheter tube is possible without degrading the integrity of the bond. The material conforms and adheres tenaciously to the shape of the patient's body in various, nonuniform positions, as in attachment to the back of a hand. And it is painless for the patient, is efficient and easy to apply, use, remove and replace, is sterile, clean and disposable, is inexpensive, and by all means it is entirely transparent and provides excellent visibility at all times for continual inspection of the penetration site, catheter, tubing, surrounding area of the site, and general well being of the patient. And it provides means to inhibit warm moist buildup, to avoid encouraging bacterial growth.
Packaging for this fenestrated transparent catheter securing device may be provided in various equivalent designs, the purpose being to physically protect the film and its adhesive side, keeping it sterile and clean, during transportation and handling, and during immediate application of the film to the penetration site. A preferred packaging and method is disclosed herein in which the packaging also provides an efficient method of handling, using the packaging as a handling frame and means for aiming and efficiently targeting the penetration site during the application of the film dressing.
These many advantages may be realized for anchoring catheters without the hazard of infection, by use of the device and method disclosed in this invention.